Underfell
by Twin Cats
Summary: As a young child falls into the underground, they befriend a talking flower and explore the world full of dangerous monsters. The monsters strongly believe that it's kill or be killed, but are they as dangerous as they look? And how does this flower know everything? Either way, Frisk will have to survive one way or another.
1. Chapter 1

_**...Well this is interesting.**_ **I never thought I'd be writing for an AU of all things. I meant to put this up yesterday, but I didn't have a lot of time.**

 _ **Anyways...Hiya, this is TC! And truth be told, I used to hate Underfell at first, mainly because I'd keep running into a lot of abusive fontcest. In fact, it got so bad that I literally thought that Underfell was basically just an AU where Papyrus abused Sans. But when I actually took a good look at the AU, it started to grow on me. I liked some of the ideas that went into it. Heck, there are a couple of good UF fan games that are in development right now that I'm looking forward to.**_

 _ **Now...keep in mind that while I may borrow some things from the community, this will mostly be my interpretation of the AU (seeing as the original creator has abandoned this). Anyways, I hope you enjoy this.**_

* * *

 **Once upon a time, two races ruled the Earth: Humans and Monsters.**

 **One day, war broke out between the two races, with the humans emerging victorious. They sealed the monsters underground using a magic spell. It is said that those who climb the mountain never come back, as the monsters still lurk inside the mountain to this very day..**

 **Mt. Ebott**

 **201X**

* * *

Frisk woke up in a patch of golden flowers, they looked around to see where they were. When they looked up, they saw the entrance to the mountain was very steep. In fact, it was too steep to climb.

...Come to think of it, why DID they want to come here? There were supposed to be monsters down here, right?

Frisk started to walk, they held their worn-out knife close to them in case of an ambush. When they made their way to the next room, they saw what looked like a golden flower sitting by itself. Unlike the ones Frisk had seen earlier, this one looked like it was wilting. Its petals were slightly torn. As Frisk tried to step closer, the flower began to panic.

"OH NO!" He quickly turned his head to look at Frisk, he looked absolutely terrified. "P-please d-don't hurt me, I-I promise I-I'll get outta y-your way!"

"What? No." Frisk assured him, "Why would I want to hurt you?"

"Y-you..." the flower began to lower his defenses. "You mean you WON'T hurt me?"

"Do I have a reason to?" Frisk asked, "It's not like you're luring me into a trap or anything."

"...I-I suppose you're right," The flower said with a weak smile. "I'm Flowey...Flowey the Flower, what's your name?"

"I'm Frisk."

"Well, Frisk. You should probably hide while you can before SHE gets here."

"Who's 'she'?"

"Oh...THERE you are~!"

"EEP!" Flowey quickly dug himself into the ground. Before Frisk had any time to respond, they were face-to-face with a tall, goat-like monster. She wore a tattered, black dress with a red symbol at the front. Dark circles sat under her eyes, she was grinning like a mad woman.

Frisk backed away, unsure of what to make of this. "Wha-"

"Come along now, child," said the goat monster as she grabbed Frisk by the arm. "We don't want you to get sick again, do we?"

"What are you talking about!?" Frisk exclaimed. "I don't even know you!"

"Silly child, did you forget my name, again?" asked the goat. "My name is Toriel. Hopefully, you'll remember this time."

Frisk panicked. Why did she act like she KNEW Frisk? They looked back at Flowey, who gave them a terrified look. "D-don't worry, I'll think of something!"

That hardly made Frisk feel any better. But for now, it looked like they had to go along with what Toriel says. After all, she couldn't be TOO crazy...right?

As the duo continued to walk, Frisk couldn't help but look around. There appeared to be a lot of puzzles, here. However, they also appeared to be completely destroyed. Frisk opened their mouth to speak, but Toriel interrupted. "I destroyed them so you would feel safer. That way I wouldn't have to lose you, again."

"Er…" Frisk struggled to smile. "So that means I won't have to solve any of them, right?"

"Actually...there's still one puzzle that I couldn't destroy," Toriel huffed in annoyance. She showed Frisk her left paw, it had a deep gash in it. "And believe me, I tried."

"Oh…" Frisk began to frown, any encouragement they had was now gone. Toriel patted their head. "Don't worry, the puzzle should be easy to figure out on your own."

Frisk nodded, they weren't even going to question it anymore.

Finally, Toriel took Frisk into another room. Aside from the nearby rubble, the only thing that stood there was a worn-out dummy.

"Now remember...when a monster attacks you, your only option is to fight back," Toriel replied. "If you absolutely have to, you can kill it. But if you DO kill it, your LV will increase.

"What's LV?"

"It stands for LOVE," Toriel replied, closing her eyes as she tilted her head. "Although...I can't remember what THAT stands for. What a pity~!"

"O-OK…" Frisk turned to face the dummy, their soul began to glow, as did the dummy's. It was just a dummy, so Frisk wouldn't have a problem attacking it, right? Still, attacking seemed...wrong. Maybe insults would work, instead?

Frisk puffed out their chest, staring straight into the dummy's eye. "You're a buttface! Not only that, but your family's a buttface! EVERYONE YOU LOVE IS A BUTTFACE!"

Suddenly, a ghost came out of the dummy's body. It left before Frisk could say anything else. Toriel began to cackle. "Of course! Why kill the monster when you can insult it? Already, you're proving yourself to be better than the last time you've attacked the dummy! "

"Hehe...yeah," Frisk looked down, gripping at their right sleeve. They were always such a softy, they questioned whether or not they would be able leave this place alive.

Toriel lead Frisk into the next room, she turned her head and grinned. "Here, how about I let you solve this puzzle? The solution should be in this room."

Frisk nodded as they started to examine the room. First, they noticed the zigzag pattern on the floor. Second, they saw the vines hanging from the holes in the wall. They walked over to the vines and looked around. What they weren't expecting to find was a trembling frog monster. It quietly looked at Frisk, then back at Toriel.

"H-hey, are you OK?" Frisk asked.

"Oh, is someone there?" Toriel asked as she walked closer. "I hope they're not here to hurt my child~!"

The frog started to back away, it hid inside a hole so Toriel couldn't see it. In fact, it went so far back that Frisk could barely see its outline. Toriel let out a small giggle. "Well, at least I know it won't bother you," she said while grabbing Frisk's hand. "I would've had to use drastic measures, otherwise."

Frisk started to frown. "Wh-what kind of drastic measures?"

Toriel brought a paw to her chin, thinking about it before looking down at the young human. "Let's just say that my clothes would've been extra dusty if I did anything!"

Frisk raised an eyebrow, unsure of what to say. Maybe she was speaking nonsense? Although in all fairness, the Ruins WERE a little dusty. And speaking of dust, Frisk and Toriel had come up to a grated bridge sitting above above a small stream. For some reason, there was a pattern of dust sitting on the bridge.

"Don't worry, I'll be right behind you!" Toriel said as she stepped back, allowing Frisk to step on the bridge. Frisk started walking absentmindedly. Things were looking good, so far...at least until Toriel pulled them back. "CAREFUL!" she screamed as spikes popped out of the ground, nearly grazing Frisk's leg. Toriel stared at the spikes with a horrified expression, almost as if she had witnessed a murder. Frisk looked up at the goat-like monster. "Toriel…?"

There was hardly a response, Frisk started pulling at her dress. "Toriel!"

"Wh-what!?" Toriel snapped out of her trance-like state. She looked down at the spikes, then back at Frisk. She scooped the human off the ground and started walking in a zig-zag pattern, avoiding the dusty parts of the bridge. As she made it to the other side of the bridge, she placed Frisk back down onto the floor. "I guess puzzles are a little too dangerous, right now."

"What gave you that idea?" Frisk asked bitterly.

"Here," Toriel said guiding Frisk into the next room. "I need you stay here while I check the rest of the Ruins. In the meantime, you can talk to me through this cell phone if you ever need anything."

"Er...thank you," Frisk said as they received the cell phone. Toriel gave the small human a pat on the head. "Be good, all right?"

As Toriel finally left Frisk alone, the young human walked over to the column at the end of the hall. They let out an exasperated gasp as they played with the phone that was in their hands.

...The phone didn't even work.

* * *

 _ **I'll admit, this chapter is a little underwhelming...But I promise, the story will be a little more different as we go along.**_


	2. Chapter 2

_**And here we have yet another edgy chapter. This was originally going to be two chapters, but I thought that there wasn't a lot of content.**_

 _ **Also: Warning for suicidal implications (no blood, though!)**_

* * *

Frisk has been sitting here for what felt like an hour, they repeatedly tapped their fingers onto the ground. Toriel said she was going to come back, wasn't she? If so, then where was she?

Suddenly, Flowey popped out of the ground. He looked around anxiously, "Is she gone?"

Frisk nodded.

"OK, good!" Flowey said with a deep sigh. "I'm sorry, I was hoping that she wouldn't find you."

"That's all right, I don't think you would've been able to do anything," Frisk replied.

"Well, maybe we should get out of here while we still can!" Flowey replied. "Who knows what she'll do when she catches us!?"

Frisk raised an eyebrow. "Why?"

"Because she'll do whatever it takes to keep you here, she'll make sure you'll NEVER leave. I know she's tried to keep the other humans down here, and each time she's failed at it."

Frisk began to feel uncomfortable. They looked around nervously before they started digging Flowey out of the ground. The flower gave them a confused look. "W-what are you doing!?"

"You know more about this place then I do, so you're coming with me."

"A-alright, just be careful not to hurt me."

Frisk nodded as they started to walk, they held Flowey close to their chest as they kept moving. They began to see piles of dead leaves sitting on the floor. As they continued to walk, they started to see more and more monsters pop out of the leaves. Some of them gave Frisk weary looks while others gave them a look of sympathy.

"Ribbit…"

Frisk looked down, the frog monster from before hopped in front of them. "So I hear that Toriel has claimed you to be her next child."

"...Next child?"

The Froggit nodded. "You see, each time a child falls down, Toriel will claim them as her own. However, she's convinced that all the children are the same child. She's not willing to accept that they've all passed."

"So that explains why she acted like she knew me!" Frisk said upon realization. The Froggit nodded in response. "So please...if you DO plan on leaving, please be careful. There's no telling of what she might do to you."

"I understand, thank you." Frisk replied. As the Froggit left, Flowey began to wilt. Frisk gave him a look of concern. "What's wrong."

"I-It's nothing," Flowey replied. "Let's just worry about getting out of here, OK?"

"All right."

Frisk continued to walk deeper and deeper into the Ruins, they could see that every single puzzle beyond the spike puzzle had been completely destroyed. They saw rock monsters sitting on switches, they were too frightened to move. They saw that the puzzles with cracked floors had solutions painted over. Frisk couldn't help but feel uncomfortable...but knowing that they'll be able to leave the ruins, they were filled with determination.

They began to rest inside a small room, they placed Flowey on a table, next to a piece of cheese. Flowey tried to move it, but it was stuck to the table. He looked like he was about to gag from being near the cheese.

"So how long do you think it'll be until we find the exit?"

"Not that long," Flowey replied. "But, um...the exit isn't...in the most convenient place."

"So where is it?"

"I can't tell you, right now...I'm sorry."

"But why not?"

"Just trust me, OK?"

"Ugh...fine," Frisk rolled their eyes. "But I hope you're not up to anything sneaky!"

After having a bit of rest, Frisk started carrying Flowey again. As they exited the room, they came across a ghost sleeping in a pile of dead leaves. The ghost was pitch black with a red smile etched onto his face. Frisk walked up to the ghost, "Excuse me!"

But before they could lay a finger on them, the ghost shot up and glared at the human with glowing red eyes. "get lost, can't you see I'm sleeping!?"

"I know, but- ACK!"

The ghost began to shoot bullets at Frisk, they managed to knock them back. "I SAID GET LOST!"

Frisk looked down at Flowey, "Who do they think they are?"

"That's Napstablook," Flowey replied. "They've been coming into the Ruins a lot, recently. I think they might be mad at something...or someone."

Frisk had a thoughtful expression, they began to walk closer to Napstablook.

"WHADDAYA WANT NOW!?" The ghost snapped.

"I'm not here to fight, " Frisk replied, "So please...can you let me go?"

"and why should i?"

"Because some goat lady will kill us if we don't get going!" Flowey snapped. Napstablook couldn't help but scoff. "sucks to be you, then!"

"Well...you might not care, but I do," Frisk replied, giving Napstablook a cold-hard glare. "And I'll get past you one way or another."

"and how are you s'posed to do that?"

"Why don't you tell me yourself, buttface?"

"Frisk, what are you doing!?" Flowey said in fear. Napstablook began to glare back. "What did you just call me?"

"You're right, I guess I was being too nice," Frisk replied, "You're actually a MAJOR buttface! THE BIGGEST BUTTFACE IN THE WORLD!"

"Stop that!" Napstablook yelled, shooting even more bullets at Frisk. The human dodged them, they began to yell even louder. "YOU'RE ALSO A BIG CRYBABY, NOT EVEN YOUR FAMILY WOULD WANT TO DEAL WITH YOU!"

"I SAID STOP!" Napstablook snapped. There were even more bullets in the field, causing Frisk to duck and weave through them. Flowey gave Frisk a terrified look. "Wow...that was actually pretty harsh."

"Well...this was exactly what I wanted," Frisk replied.

"What do you mean?"

"Look at them," Frisk replied. Flowey looked over at Napstablook, the bullets were actually coming from his eyes. Was...was he actually CRYING? It was rare to see a monster cry. And when they did, they were considered weak by other monsters.

"...i get it, my cousins all left because they wanted nothing to do with me!" Napstablook snapped, "are you happy, now? Or are you just gonna insult me some more?"

"Oh…" Frisk began to frown. "I had no idea that your family actually left you." They placed Flowey down and cautiously walked over to Napstablook, expecting them to attack again. "But if you want...then maybe we could be friends?"

"...you'd really be friends with me?" Napstablook asked. Frisk replied with a nod. "Of course, everyone needs a friend!"

"hehe…" As unsettling as it looked, Napstablook began to smile. "i WOULD show you something cool, but that can happen some other time."

Frisk had a hopeful look in their eye. "You mean you'll let us go?"

"yeah, sure." Napstablook replied. "just promise me that you won't go insulting people again. It's rude, y'know?"

Frisk nodded. "Alright, I promise!"

Napstablook finally vanished. With that said, Frisk picked Flowey up from the ground and continued walking. As they walked, they stumbled upon some sort of bake sale. Frisk looked at the sign, curiously. They'd be willing to buy a donut, but they didn't have money for it.

"Here," Flowey said as he gave Frisk 7g. "Things are going to get tougher from here on out. I'd suggest grabbing anything you can for survival.

"OK," Frisk said handing the gold coins over to the spiders. One of them crawled down and handed Frisk a spider donut. It was a round, purple donut with powder on it. The spiders thanked Frisk as they began to walk, again.

They weren't entirely sure of where they were going, but they were certain that they were getting closer to the exit. The rest of the Ruins wasn't too hard to get by. Since the puzzles were broken, and the monsters had no desire to fight, Frisk didn't have to worry about anything.

Well...besides Toriel, but they haven't encountered her since that spike puzzle.

Frisk walked up to a tree. It was an old, black tree with the leaves surrounding the trunk.

"How sad," Flowey said sympathetically, "Every time the tree grows any leaves, they all fall off. I don't know about you, Frisk, but feel like it should be a metaphor for something."

"What do you mean?" Frisk asked. Flowey tilted his head, "I think it's supposed to be a metaphor for life or-"

"Oh god...Why haven't they picked up? WHY HAVEN'T THEY PICKED UP!?" Suddenly, Toriel started to run in a panic. "THEY HAVEN'T DIED AGAIN, HAVE THEY!?"

As Toriel looked at Frisk, the human began to back away slowly.

"OH THANK GOD!" Toriel said in relief as she hugged Frisk, squeezing the air out of their lungs. "I thought I had lost you, again! Please don't ever scare me like that!"

"Um…" Frisk was speechless, they had little time to react before Toriel grabbed their free hand and started leading them to her house. She looked down at Flowey, giving him a disgusted look. "You're not planning to eat that thing, are you!?"

"N-No," Frisk replied, "I just thought this flower looked neat, so I took it with me."

Toriel began to ponder for a moment. "Well...as long as you're not eating it, then I suppose it's fine."

Finally, the trio finally stepped inside the house. Frisk's nose scrunched up, something smelled like burning rubber.

"You never picked up your phone, so I figured I would just make you a Butterscotch-Cinnamon pie," Toriel replied. "Although...I couldn't find the butterscotch...so I used snails, instead!"

"That...sounds delicious," Frisk said, trying to smile.

"Of course it is, snails can make anything better!" The goat monster's ears perked up. "Oh, but you're probably tired from all that running around! Why don't you rest while the pie cools off."

"O-Oh, sure," Frisk replied, "But could you take me to my room? I can't remember where it is."

"Of course," Toriel began to lead Frisk into their room, "Anything for you, my child!"

"Thank you," Frisk replied. Once Frisk made it into their room, Toriel let out a hollow chuckle as she closed the door behind them, "And this time, I'll make sure you never leave again!"

* * *

Frisk threw themselves onto the bed with Flowey still in their hand. Flowey looked disgruntled. "Careful, you almost squished me!"

"Sorry," Frisk replied as they gently placed Flowey on the Floor. "But I gotta ask...how far away are we to the exit?"

"Actually, the exit's inside this house," Flowey replied. Frisk began to scowl. "Then why didn't you say anything!?"

Flowey cocked his head to the side, "I thought you wouldn't believe me if I told you.."

Frisk let out an exasperated sigh. They sprawled across the bed and stared at the ceiling. How were they going to survive with this flower tagging along? After all, he hasn't been entirely helpful. Although he DID say he knew where the exit was. And technically, he wasn't wrong. In fact, they probably wouldn't have been able to go anywhere else.

"Hey, Frisk?"

Frisk turned their head, "Yeah?"

"I don't want you to say anything to Toriel, OK? It's best if we sneak off without her knowing."

"...OK, Flowey."

As time had past, Frisk began to feel dreary. Their eyelids began to close shut, tomorrow was another day.

* * *

Frisk woke up to what sounded like a crash, they hastefully jumped out of bed, curious as to where that sound came from.

"WHAT WAS THAT!?" Flowey asked, startled.

"I'm not sure," Frisk replied, "But it sounded like it happened downstairs!"

Frisk grabbed a nearby backpack and stuffed Flowey inside. They left the bag partially open so the flower could peak out whenever he wanted. They also pulled out their knife. Frisk wasn't one for killing. But if worse came to worse, then it COULD be useful.

As Frisk bolted out of the room, they heard another crash coming from downstairs. As they made their way down into the basement, they saw Toriel was attacking the walls in front of it.

"What are you doing!?" Frisk yelled.

"I'm destroying the exit!" Toriel replied, "That way, you will NEVER leave me, again!"

"But why!?" Frisk asked, "Why would you want me to stay down here!?"

"So you can stay with me forever," Toriel replied, "Now please, go back upstairs!"

"No!"

Toriel began to tremble with rage. "Go back upstairs or so help me-"

"YOU IDIOT, THEY'RE NOT EVEN THE SAME KID!" Flowey snapped before he realized what he had just said. Toriel's scowl worsened, flames began to form in her paws. "How DARE you disrespect me!"

"Toriel, wait!" Frisk started to back away from the monster, pulling the dagger out of their pocket. "I can explain-"

All of a sudden, fire began to spread all over the basement. It looked as though Frisk was standing in hell. Toriel moved closer, the light of the fire emphasized her dilated red eyes and large fangs. She almost looked like a psychopath.

"After everything I have done for you, YOU STILL CHOSE TO BE UNGRATEFUL!" Toriel yelled as the basement blazed hotter and hotter. "I gave you a home, I made you food, I even offered to be your mother! AND THIS IS THE THANKS I GET!?"

Frisk continued to back off, their hands were now trembling. Despite the anger, Frisk could see the pained expression on Toriel's face. Would it be right to kill her off? Would they be willing to go through with it? They weren't entirely sure, but they knew killing wasn't a good option.

"I NEVER ASKED FOR THIS!" Toriel yelled, "I NEVER ASKED TO BE BANISHED! I NEVER ASKED FOR MY CHILDREN'S DEATH! I'VE NEVER...I-I'VE NEVER…"

Toriel finally dropped to her knees, the flames began to disappear as tears formed in her eyes. "I-I've never w-wanted to be left alone! T-To rot down here f-for all eternity!"

Frisk finally let their guard down, they stepped closer to Toriel. But before they could say anything, Toriel took the child's hand and pointed the knife to her chest. "Please...take my soul and leave this cursed place, it's the only way you'll ever be able to leave...the only way you'll be able to stand a chance against Asgore."

"But-"

Toriel closed her eyes tightly. "Please, it'll be better for both of us if you kill me, now!"

"...But I don't want to!"

Toriel's eyes widened, she gave Frisk a strange look. "B-but what good will it do if you let me live like this?"

Frisk looked away, unsure of how to say anything. They let out a deep breath. "Look, I haven't known you for very long...but I know for a fact that killing isn't going to solve anything. So please, will you let me go?"

Toriel began to smile genuinely, she wrapped her arms around Frisk. "Y-you really aren't my child, are you? But it's so strange, you two act almost exactly alike."

"I know it's hard for you to let go," Frisk said as they returned the hug, "but believe me...it's for the best."

A few more minutes have passed, neither one of them budging an inch. Finally, Toriel let them go. "But please...once you leave, don't ever come back! Do you understand?"

Frisk nodded, "Yes, ma'am."

"Then…good bye...my child."

Finally, Toriel began to head upstairs. Not once did she look back. As upsetting as this was for her, this was obviously the right thing to do. And for that, Frisk was proud of her.

"Hey, Frisk?" Flowey said as he popped out of the backpack, "Why didn't you just kill her?"

"Because killing is wrong," Frisk replied. "Unless I have no other choice, then I can't kill someone."

"But down here, it's kill or be killed! It's every monster for themselves! Do you see what I mean?"

Frisk nodded. "I do, but I'm not a monster."

"Huh…" Flowey began to speak in a more upbeat tone. "Then you might be useful to me, after all."

Frisk raised an eyebrow, they couldn't quite understand what that that meant. Was that meant to be a compliment? Regardless, Frisk had to keep going. who knows what kind of monsters could be ahead?

* * *

 _ **And with that, Frisk heads off to Snowdin. Hopefully I can come up with something more original for that arc.**_


End file.
